The laboratory mouse is the premier animal model for studying human diseases. There is an immense amount of research done throughout the United States and around the world using laboratory mice. However, there are not enough well trained mouse pathologists available to interpret the tissue abnormalities that arise in mice that are experimentally manipulated, genetically engineered, in long term aging studies, or that develop spontaneous diseases. The goal of this annual workshop, currently in its 14th consecutive year, is to provide an intense, high level, interactive, five day training session aimed at the next generation of veterinary and physician pathologists who will work directly (as PIs and collaborators) and indirectly (as support pathologists) in the development and characterization of mouse models of human disease. Surrounding a highly productive and passionate core group of pathologists (the organizing team), we vary the program with a rotating group of pathology specialists and research scientists. Since The Jackson Laboratory is recognized as a unique institution that focuses on the genetics, biology, and pathology of laboratory mice, we will host this annual meeting in our seaside conference center. In the successive 3 years of this application, topics covered range from a variety of diseases, not just neoplastic, from those associated with aging to embryonic developmental abnormalities. Specific organ systems are covered, skin, bones, eyes, etc. to new technologies for creating genetically engineered mice. We are adding a bone biomethods one day workshop immediately after the meeting (not part of this application) to add depth to that area. The group of participants is kept small to maximize interactions between the faculty and attendees to encourage networking and collaboration. Our long- term objective is to develop a highly skilled cadre of comparative pathologists capable of interpreting mouse lesions and applying this knowledge to research and training programs at their respective institutions throughout the United States and beyond.